Compatibility of Azospirillum brasilense with fungicide and insecticide and its effects on the physiological quality of wheat seeds

Abstract

Seed treatment is a practice that helps the initial establishment of the crop without the effects caused by pests and diseases. The association of diazotrophic bacteria with grasses has been used in the supply of nitrogen to plants; however, these microorganisms produce growth-promoting substances, which promote benefits in the growth and development of the crops. Thus, the objective of this study was to evaluate the compatibility of Azospirillum brasilense associated with the fungicide difenoconazole and the insecticide thiamethoxam by observing the effects on the quality of seed emergence of three wheat cultivars (Triticum aestivum L.). Three wheat cultivars, arranged in a 4 x 2 factorial system with four replicates, were tested. The treatments were the control; difenoconazole (Spectro® at a dose of 150 mL per 100 kg of seed); thiamethoxam (Cruiser® FS 350 at a dose of 200 mL per 100 kg seed) and difenoconazole + thiamethoxam, applied on wheat cultivars TBIO Mestre, TBIO Itaipu and TBIO Sinuelo. Bacteria from the Azospirillum genus were used in the inoculation. The wheat seed retains its quality when it checks the germination, vigor and independent accelerated aging, whether or not fungicide, insecticide and A. brasilense were used. The insecticide thiamethoxam increased the length of shoots and roots and provided compatibility with A. brasilense, and fungicide inhibited the length of shoots and roots and was antagonistic to the bacterium A. brasilense.